For the second month in a row, the Hagerty Market Rating fell again in the mid-August to mid-September time period.

Hagerty graph

For the second month in a row, the Hagerty Market Rating, a complicated algorithm designed to take the pulse each month of the collector car marketplace, fell again in the mid-August to mid-September time period. Based on a 100-point scale, the September rating is 67.74.

Although the number dropped more than half a point from the 68.32 figure for August, it still is within the “expanding market” range, which means the market is neither flat nor overheated.

“In spite of decreased auction activity, private sales and requests for value increases, the market is currently balanced by a strong economy and the fact that the vast majority of classic cars continue to hold their value,” McKeel Hagerty, chief executive of the insurance and vehicle-value tracking company, said in a news release.

The Hagerty news release pointed to several factors in the September decline:

After increases in July and August, Auction Activity decreased more than any other section of the ratings formula and more than at any time in the past 13 months.

Private sales activity also dropped after two consecutive months of increases. The average sale price is down 11 percent over the past 12 months.

Requests for value increases fell in both the broad market and the high-end market. For example, 1969-73 Porsche 911 values are down 31 percent in the past year and 1964-68 Ferrari 275 values have decreased 83 percent in the past year.

On the other hand, some vehicles are outperforming the overall market. The top five in that category are the:

1963-65 Buick Riviera (currently at 96 on a 100-point scale)

1984-93 Mercedes-Benz 190 (95)

1969-72 Pontiac Grand Prix (94)

1979-92 Mercedes-Benz W126 (93)

1945-68 Dodge Power Wagon (93)

Hagerty notes that Riviera remain in high demand and that while supply increases as people become willing to sell their cars, sales prices also have increased in both private and public transactions.

It says collectors are adding Mercedes’ 190 sedans “in droves” as the cars are being recognized as both distinctive and practical transportation “for little money.” Meanwhile, the larger S-Class Mercedes, once among the most expensive luxury cars, “are being rediscovered by nostalgia hunters who regard them as stylish, cheap, and durable.”

The Pontiacs are being purchase by “bargain buyers” who see the car as equal parts power and comfort, and at a discount, and “have latched onto this model and prices are rising as a result,” Hagerty’s news release reported.

As to the big Dodge pickup truck — “burly,” Hagerty called them, “Auction activity for these classic pickups has started to simmer following some big sales from a few years ago, but private activity remains very strong, with a 33 percent increase in insured values.”

The Hagerty Market Rating is based on a weighted algorithm that considers 15 proprietary data points in eight categories, including public auction and private sales, values of insured cars, price-guide values, Hagerty’s own index system and input from industry experts.

The rating, reported at the middle of each month, is based on a 100-point scale and is presented in the form of a tachometer-style gauge, complete with a “superheated” red zone, a sort of warning that we’re approaching a possible burst of the bubble. Ideally, the market cruises along comfortably in the 60- to 80-point “expanding” zone.

Although first released in January 2015, Hagerty applied its formulas to the classic car marketplace dating back to January 2007. The rating then was in the low 60s. During the economic recession, it slumped to the high 40s and has been on an upward trend since late 2010.